Currently, wireless communication systems such as a mobile phone system and a wireless local area network (LAN) are widely used. In addition, in the field of wireless communication, in order to further improve a communication speed and a communication capacity, a next-generation communication technology is continuously discussed. In, for example, 3rd Generation Partnership Project (3GPP) serving as a standardization body, standardization of a communication standard called Long Term Evolution (LTE) and standardization of a communication standard called LTE-Advanced (LTE-A) based on LTE are completed or studied.
In such wireless communication systems, a technology called hand over is used in some cases. The hand over is, for example, a technology for switching a base station device, to which a terminal device is coupled, from a base station device to another base station device. Based on the hand over, the terminal device becomes able to continuously perform wireless communication.
In LTE, a base station device transmits a MEASUREMENT CONTROL REQ message to a terminal device in some cases. The MEASUREMENT CONTROL REQ message includes a threshold value and so forth. In a case of obtaining a detection result greater than or equal to the threshold value, the terminal device that receives the relevant message transmits a MEASUREMENT REPORT message to the base station device. Based on, for example, the MEASUREMENT REPORT message, the base station device determines whether or not to perform hand over.
As a technology relating to the hand over, there are, for example, the following technologies.
In other words, there is a channel switching method for determining, based on the degree of reduction of an electric field strength of a channel during communication, whether a terminal is in high-speed movement or in low-speed movement and performing channel switching, in a case of being in the high-speed movement, by selecting a wireless base station whose electric field strength is greater than or equal to a specified value and that has a maximum increasing change in the electric field strength.
According to this technology, it is thought that it is possible to reliably perform channel switching even if, for example, a simplified mobile phone terminal moves at high speed and it is possible to reduce instantaneous interruptions during a telephone call by suppressing as much as possible of the number of times channel switching is performed.
In addition, there is a mobile communication system in which the location of a mobile station after an arbitrary time period is predicted based on a distance from a base station and the movement direction and the movement velocity of the mobile station, thereby handing over to a base station whose distance from the predicted location is the shortest and that is predicted to improve downlink communication quality.
According to this technology, it is thought that it is possible to reduce the power consumption of a wireless mobile station by suppressing, for example, the number of times undesirable hand over is controlled and it is possible to maintain stable communication by reducing a load on an entire wireless system.
Furthermore, there is a wireless base station system in which, using a control device, path information is created based on the history of previous telephone calls, a wireless base station able to be skipped is identified based on the path information, and hand over performed on the identified wireless base station is avoided.
According to this technology, it is possible to reduce undesirable hand over while not adding, for example, a function to a wireless mobile station. As technical literatures of the related art, there are “Intra-LTE Handover Using the X2 interface”, 3gLterInfo, Dec. 4, 2013, Japanese Laid-open Patent Publication No. 9-284826, Japanese Laid-open Patent Publication No. 2004-201001, and Japanese Laid-open Patent Publication No. 2010-212988.